Today's positive displacement pump motors for driving positive displacement pumps comprise a frequency converter having an integrated regulator capable of regulating the input signal, in particular a voltage signal for the frequency converter as a function of a measured actual operating parameter and a reference input variable to be achieved. The regulator sends “without criticism” the manipulated variable, which is determined as a function of the reference input variable, to the frequency converter. One problem is that today, a regulator assigned to a frequency converter is designed only for each specific motor, i.e., it is not optimized with regard to the positive displacement pump, which is actually of interest with positive displacement pump systems. This can lead to problems in the case of positive displacement pump systems because positive displacement pumps are fundamentally a greater threat to the pump itself and/or to other process units in comparison with rotary pumps. This can be attributed to the difference in the characteristic response of positive displacement pumps in comparison with turbo engines. Fundamentally, this may also lead to complete self-destruction or permanent damage to the positive displacement pumps in the extreme case, in particular when signs of damage are not detected promptly.
This also does not take into account the influence of manipulated variable signals, resulting directly from the reference input variable (setpoint input), on the quality of the delivery fluid with known positive displacement pumps.
In addition, one disadvantage of known pump systems is that specific programming of the logic unit of the control means must be performed on the respective electric drive motor, including the frequency converter, but such programming can only be a compromise from the standpoint of optimized properties of the pump module. With known pump systems, it is only possible to replace the drive module independently of the pump module—it is impossible to replace the control means because the control means are integrated into the frequency converter of the electric motor.